I'm not sure quite what you mean by properties. If you mean the properties when the recipient receives an email from a Hotmail account, it depends if the email was sent from the senders own computer using an email client like Outlook or using the web mail.
If you are using Outlook the recipient will see the email was sent from the senders own ISP using their default SMTP, If its sent using web mail it will be the IP address of MSN.
Is that what you are asking? Or have I got it wrong?